Implant with an annular base

ABSTRACT

The implant has an annularly bent base, whereby the imagined surface enclosed by the base is bent. Preferably the surface enclosed by the base is a symmetrical. It is particularly advantageous if the base is enclosed by a solid material and this is enclosed by a relatively soft material. This offers the possibility of designing fastening clips in the relatively solid material. Such implants are especially suited as heart valve rings.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation and claims priority under 35 U.S.C. §120 of U.S. patent application Ser. No. 10/890,032 filed Jul. 13, 2004.

The invention relates to an implant with an annular base.

Implants with annular bases are used in different parts of the body.Examples of these in particular are inlets and outlets of vessels,synthetic intestinal outlets and the like. The invention relates inparticular to stabilizing rings for a heart valve annulus.

The object of heart valves in human or animal hearts, depending on stateof contraction, is to permit blood flow in the open state or to preventreflux in the closed state. This function is regulated by the heartvalves flaps, which close precisely in the closed state of the valves.The overall geometry of heart valves ensures that the flaps lieprecisely above one another to prevent reflux.

Various heart conditions can lead to deforming of the heart valvesannuli. This can result in deforming of the whole valve geometry. Andthe result of this is that the valve flaps no longer lie on one anotherprecisely and the function of the heart valve is restricted thereby.This is frequently accompanied by leakage through the closed heart valveor worsening of the valve dynamic and thus delay in the closing phase.The performance of the heart thereby deteriorates substantially.

Valves damaged in this way can be replaced by synthetic heart valveprostheses. The prostheses adequately fulfil the function of the damagedvalve; however this method does have certain limitations due to therestricted fatigue strength or extraneous materials used.

A view-rich alternative to synthetic heart valve prosthesis isrepresented by surgical correction of the valve annulus. Here a more orless flexible ring is attached in the valve annulus, which shouldrestore the physiological geometry.

These methods are based on inventions by Carpentier (U.S. Pat. No.3,656,185) and Cooley (U.S. Pat. No. 4,164,046) and are clinicallyestablished.

The rings used are however in many cases not optimally suited both asrigid and as flexible rings to cause simply shaping of the valveannulus, which ensures tight closing of the valve flaps.

The object of the invention is therefore to further develop an implantwith an annular base, such that it adapts optimally to as manyapplications as possible.

This task is solved by an implant with an annular base, in which theimagined surface enclosed by the base is bent inwards in a firstquadrant and is first bent inwards and then outwards in a subsequentsecond quadrant.

The inventive implant has an annular base, which is designed such thatthe imagined surface enclosed by the base is bent according toparticular preset values. This enables it to produce rings, which areadapted optimally to the physiological conditions and also remain in themechanically unstressed state in this form. Depending on the case a widerange of forms of ring can be made, which are either adaptedindividually to the diseased vessel outlet, or depending on size andflexion can be prefabricated and marketed for different uses.

It is advantageous if the imagined surface enclosed by the base is bentoutwards in a third and in a fourth quadrant. It has eventuated that formedical applications a concave peripheral line lying approximately fullyin the first quadrant is an advantage. On one side convex peripherallines connect thereto via the following two quadrants, and the fourthquadrant is approximately half convex and in the other half configuredflattened or even concave.

For clinical application it is particularly advantageous if the imaginedsurface enclosed by the base is bent in on itself.

Known implant rings exhibit a bi-dimensional geometry. In part theserings can also be deformed in the third dimension. For this the ringsare designed elastic. However, this results in the ring again assuming abi-dimensional structure in the non-mechanically stressed state. Thebent-in form of the base leads to the implant being delivered with apreset shape, which must no longer be adapted during an operation, oronly slightly so.

An advantageous embodiment provides that in cross-section the imaginedsurface enclosed by the base has a point of inflexion. Viewed from theside such a base has concave and convex regions and depending on usagethere can even be several points of inflexion. This allows optimal ringshapes to be produced, which both in plan view and in side elevationdeviate from simple geometric basic shapes. The imagined surfaceenclosed by the base thus has at least a saddle shape or an S-shapedbend in a section line.

It has eventuated that the form of the ring does not necessarily have tobe a circular shape. It is advantageous if the imagined surface enclosedby the base is asymmetrical. In particular, annular bases, which areconstructed neither point- nor mirror-symmetric, enable optimaladaptation to the annulus geometry to be found in the body. This isespecially significant for implants in the region of the heart valveannulus.

A rise in adaptability—but possibly also a drop in durability—isachieved by the base being plastically deformable. This enables the baseto be formed subsequently just prior to an operation, so that it canbest adapt to the present physiological conditions.

A material, which can be made plastically ductile by physical orchemical treatment for a specific period, is particularly preferred.This enables the ring to be formed optimally prior to implantation,whereby afterwards and in particular in the implanted situation the ringis no longer ductile or is only still elastically ductile. This materialcan for example be made plastically ductile by heat treatment. As thematerial cools down to body temperature below 42° C., it loses itsplastic ductility.

In addition synthetics with memory effect can also be used. Suchsynthetic materials can be deformed in any way. But as long as they arebrought to a temperature range of the human body temperature, theyassume a previously defined form.

Above all for the use of annular bases for strengthening the heart valveannulus is it an advantage if the imagined surface enclosed by the basehas at least one concave bent edge region. In the event of heart valveannulus treatment this concave bent edge region is arrangedadvantageously between the Trigoni Fibrosae.

An embodiment provides that the base is enclosed by a multilayermaterial, preferably a tissue. This embodiment is advantageouslyindependent of the previously described ring geometries and essential tothe invention. When the known implants with annular bases are used thiscan lead to problems in anchoring to the surrounding tissue, such as forexample of the heart on account of considerable stress from the highload exchange. Known implants have a metallic ring, which is enclosed bya seam ring. Here the problem arises that this can lead to the structureof the seam ring coming away from the metallic core. Also it can resultin destruction of the structure and to individual fibres being torn outfrom the localised strain of the seam ring.

This is combated according to the present invention by the base beingenclosed by a multilayer tissue. Preferably the base is enclosed by asolid material and this is enclosed by a relatively soft material. Thisresults in at least one three-ply situation of base material, the solidmaterial enclosing the base and the relatively soft material enclosingthis material.

In this case the base is preferably formed from a metallic material. Asmentioned hereinabove however different synthetic materials can also beused.

The multilayer structure enables a core material to be used, whichcontributes substantially to shaping. The superposed first layerestablishes a solid connection to the core material and comprises arelatively solid material. The second layer comes into contact with thesurrounding tissue in the implanted state and has the usual softcharacter. In fixing the ring the seam can be guided through the secondlayer as usual. For solid anchoring the seam however can also be guidedthrough the inner, solid material. This ensures for example asubstantially improved fixing of a valve ring also at high localisedstresses.

Another embodiment provides that the base has puncture channels. Theimplant can be fastened to the surrounding tissue either by sewing ontotissue enclosing the base, or the base consists of a softer material,which can be penetrated by the needle. It is particularly advantageoushowever if already prefabricated channels are arranged in the basepuncture, which can serve to anchor the threads during implantation.

Depending on the application is it suggested that the puncture channelsare designed round or oval in plan view.

In order to find the puncture channels more easily and to thread theneedle through the puncture channels, it is proposed that the puncturechannels have funnel-shaped openings. The puncture channels are thuswidened in the edge region. This enlarges the opening, whereas in themiddle region a smaller puncture channel opening guarantees thestability of the implant.

An advantageous embodiment provides that the puncture channels arearranged in the middle of the base cross-section. Hereby the stabilityof the implant is restricted the least. Depending on use it is alsoadvantageous to arrange the puncture channels offset to the centre ofthe base cross-section, preferably relocated outwards. The seam is laidin the outer region of the implant. Depending on surgical premisesvarious position of the seam can be established relative to the implantbody. By way of example the puncture channel can also be arranged offsetto the imagined surface enclosed by the base.

Depending on use the puncture channels enable tissue enclosing the baseto be dispensed with even completely. The puncture channels however canalso guarantee different fastening options for the implant during theoperation in combination with tissue enclosing the base.

It is also advantageous if the implant has a fastening clip. Such afastening clip is also advantageous and essential to the inventionindependently of the geometry and the layer structure of the implant. Afastening clip enlarges the geometric region, in which the thread can befixed during implantation. An embodiment provides that the fasteningclip is arranged in a material enclosing the base. Since the base isusually a metallic material, arranging the fastening clip in a materialenclosing the base enables the implant to be made particularly simply.

Here the material enclosing the base, in which the fastening clip isdesigned, can be a solid material.

Solid material within the framework of the description of the inventionis understood as a material, which allows a thread to be drawn throughthis material with a needle to connect the material with the tissueenclosing the implant. On the other hand however the solid materialshould have a greater strength than known tissue materials, which areused for anchoring metallic bases in the body by sewing.

The fastening clip or several fastening clips can be provided on theparticularly stressed regions of the implant to guarantee secureanchoring. Implantation however is made easier by the fastening clipenclosing the base annularly. This enables the implant to be anchored onthe entire peripheral line not only with the softer tissue material, butalso enables the seam to be guided through the fastening clip made of apreferably more solid material.

In particular for processing a preformed heart valve annulus it is anadvantage if the implant has at least one reinforced fixing point. Thisfeature of the inventive implant is also essential to the inventionwithout the previously described features. Preferably fixing points arearranged on two sides of a concave bent edge region. With strengtheningof a heart valve annulus these fixing points are designed such that thestress can be input centrally to the valve ring. The position of thefixing points is in this case selected advantageously such that itallows fixing to the Trigoni Fibrosae in keeping with the anatomicalconditions.

Advantageous embodiments of an inventive implant are illustrated in thediagram and are explained in greater detail hereinbelow.

FIG. 1 is a plan view of an annular implant,

FIG. 2 is a side elevation viewed from the front of the annular implantshown in FIG. 1,

FIG. 3 is a side elevation viewed from the side of the annular implantshown in FIG. 1,

FIG. 4 is a section through an annular region of the implant shown inFIG. 1,

FIG. 5 is a section through an annular region of the implant shown inFIG. 1 in the region of a fastening clip,

FIG. 6 is a plan view of an implant corresponding to the implant shownin FIG. 1, though with two fixing points,

FIG. 7 is a plan view of an implant with drawn-in quadrant and puncturechannels,

FIG. 8 is a section through the implant shown in FIG. 7,

FIG. 9 is a view of the section shown in FIG. 8 with enclosing tissue,

FIG. 10 is an alternative embodiment in section through the implant withdecentralized puncture channels,

FIG. 11 is another embodiment in section with a puncture channel, whichis arranged offset to the imagined surface enclosed by the base,

FIG. 12 is an enlarged view of a section of a base with round puncturechannels, and

FIG. 13 is an enlarged view of a section of a base with oval designedpuncture channels.

The implant 1 shown in FIG. 1 has an annular base 2, which encloses animagined surface 3. The side elevations shown in FIGS. 2 and 3 explainthat the imagined surface 3 has a bent form. In the present case it isbent in an S-shape. It therefore has opposite bent regions 4 and 5,between which a point of inflexion 6 lies.

In particular FIG. 1 shows that the imagined surface enclosed by thebase is asymmetrical. The region 7 of the base 2 has approximately theform of an ellipse, while the remaining peripheral region in the region8 is bent opposite and in the region 9 is designed approximatelystraight.

FIG. 4 shows that the base 2 is enclosed by two material layers 10 and11. In this embodiment the base comprises a metallic core material. Thisis enclosed by a relatively solid material 10. The relatively solidmaterial 10 creates a good connection to the metallic core material 2and is enclosed by the second layer 11. In the implanted state thesecond layer 11 comes into contact with the enclosing tissue and has theusual soft characteristic. When the ring is being fixed this enables theseam to be guided through the inner rigid tissue 10 to ensureparticularly good fixing of a valve ring with high localised stressesalso.

FIG. 5 shows that the implant 1 can also have a fastening clip 12. Thisfastening clip 12 is formed in the embodiment by the second layer 10made of relatively solid material. Because the fastening clip 12 isdesigned such the geometrical region, in which the thread can be fixed,is enlarged. The fastening clip 12 can enclose the entire baseannularly.

FIG. 6 shows an implant with two fixing points 13 and 14. These fixingpoints 13 and 14 lie to the right and left of a concave bent edge regionof the annular base. These fixing points are designed such that thestress can be input centrally into a valve ring. The position of thefixing points is adapted to the anatomical conditions and should allowfixing to the Trigoni Fibrosae.

In FIG. 7 an implant is divided into four quadrants by means of thelines 15 and 16 lying orthogonally to one another. In the first quadrant17 the edge line of the implant is bent inwards and is thus concave,whereas the edge line of the implant is bent outwards in both the otherquadrants 18 and 19 attaching thereto on the left. In the fourthquadrant 20 the edge line of the implant is first bent outwards, as inthe quadrant lying in front, and a bend 21 is provided approximately inthe centre of the fourth quadrant, which leads through to a flattened orslightly inwardly bent partial region 22. This partial region 22 goes asfar as another bend 23, which lies approximately at the transition fromthe fourth quadrant to the first quadrant. Provided in the base 24 ofthe implant are lengthy puncture channels 25, of which a large number isarranged on the base 24 of the implant.

The section shown in FIG. 8 shows a possible embodiment of such puncturechannels 25. The channel 25 divides the base 24 in the region of thepuncture channels into two base cross-sectional areas 26, 27 circular incross-section. A funnel-shaped structure 28, which facilitates a needlebeing inserted into the puncture channel 25, is created due to thestructuring of the base in the transition region to the puncturechannel.

The puncture channels enable an embodiment without tissue enclosing thebase. Yet also with use of tissue enclosing the base—as shown in FIG.9—the channel 25 facilitates the anchoring of threads on the base, aslong as the threads are guided through the enclosing tissue 29 and thepuncture channel 25.

FIGS. 10 and 11 show that the puncture channels do not have to bearranged in the centre of the base. Slight offsetting of the puncturechannels 30 radially outwards, as shown in FIG. 10, enables the implantto be sewn into its radial outer region. FIG. 11 shows a puncturechannel 31, in which the outer part 32 of the base is arranged offset tothe imagined surface 33 enclosed by the base. This facilitates theimplant to be sewn onto the surrounding tissue.

Also, with the funnel-shaped design of the access to the puncturechannel the puncture channels, as shown in FIGS. 12 and 13, can bedesigned as round openings 34 or as oval openings 35. The oval openings35 extend in a longitudinal direction of the base so as to impair thestability of the base minimally only.

Another description of the implant provides that the base in the planview is designed bean-shaped with a flattened side. The complexinterplay enclosing the base of concave and convex lines correspondssubstantially to the outer contour of a bean, whereby a flattenedsurface or another shorter surface bent inwards is provided attached tothe inwards bent surface.

The embodiments show implants, which are designed for use as a valvering. Implants according to the present invention can however be usedfor different applications in surgery and in particular forstrengthening outlets and vessels.

1: An implant (1) with an annular base (2), wherein the imagined surface(3) enclosed by the base (2) is bent inwards in a first quadrant and inan attached second quadrant is first bent in and then out. 2: Theimplant with an annular base as claimed in claim 1, wherein the imaginedsurface (3) enclosed by the base (2) in a third and in a fourth quadrantis bent outwards. 3: The implant as claimed in claim 1, wherein theimagined surface (3) enclosed by the base (2) is bent into itself. 4:The implant as claimed in claim 1, wherein the imagined surface (3)enclosed by the base (2) has a point of inflexion (6) in cross-section.5: The implant as claimed in claim 1, wherein the base (2) isplastically ductile. 6: The implant in particular as claimed in claim 1,wherein the base (2) is enclosed by a multilayer material, preferablytissue. 7: The implant in particular as claimed in claim 1, wherein thebase (2) is enclosed by a solid material (10) and this is enclosed by arelatively soft material (11). 8: The implant in particular as claimedin claim 1, wherein the base (2) has a metallic material. 9: The implantin particular as claimed in claim 1, wherein the base has puncturechannels. 10: The implant as claimed in claim 9, wherein the puncturechannels in plan view are designed round. 11: The implant as claimed inclaim 9, wherein the puncture channels in plan view are designed oval.12: The implant in particular as claimed in claim 9, wherein thepuncture channels have funnel-shaped openings. 13: The implant asclaimed in claim 9, wherein the puncture channels are arranged in thecenter of the base cross-section. 14: The implant as claimed in claim 9,wherein the puncture channels are arranged offset to the center of thebase cross-section preferably relocated outwards 15: The implant inparticular as claimed in claim 1, wherein the implant (1) has afastening clip (12). 16: The implant as claimed in claim 15, wherein thefastening clip (12) is arranged in a material enclosing the base (2).17: The implant as claimed in claim 15, wherein the fastening clip (12)is designed in a solid material (10) enclosing the base (2). 18: Theimplant as claimed in claim 15, wherein the fastening clip (12)encircles the base (2) annularly. 19: The implant in particular asclaimed in claim 1, wherein the implant has at least one reinforceddesigned fixing point (13, 14). 20: The implant as claimed in claim 19,wherein fixing points (13, 14) are arranged on two sides of a concavebent edge region (8). 21: The implant with an annular base, wherein itis designed in plan view bean-shaped with a flattened side.